It is known that a connection portion of different types of metals is easily corroded by the intrusion of water and chloride ions. Hence, for example, when the material of a conductor of a coated electric wire and the material of a crimp terminal differ from each other, the circumference of a crimp connection portion of the electric wire and the crimp terminal is coated with an anti-corrosive material made of resin.
In recent years, examples have been increasingly present where in terms of the reduction in weight of a vehicle, instead of a copper wire (a coated electric wire in which copper or a copper alloy is used as an internal conductor), an aluminum electric wire (a coated electric wire in which aluminum or an aluminum alloy is used as an internal conductor) is used. Hence, an electric wire with a terminal is proposed in which a connection portion of the aluminum electric wire and a crimp terminal made of copper that is conventionally generally used is coated with an anti-corrosive material (Japanese Patent Laid-Open Publication No. 2014-26796).
A conventional electric wire with a terminal and a method for manufacturing the same will be described with reference to FIGS. 1 to 5.
As shown in FIGS. 1 and 3, the electric wire with a terminal includes an electric wire W which has a conductor (core wire) Wa and an insulating coating Wb that coats the conductor Wa, a crimp terminal 10 which is connected to a terminal of the electric wire W and an anti-corrosive material 20 made of resin which is provided so as to coat a connection portion of the electric wire W and the crimp terminal 10.
The crimp terminal 10 has, in its front portion, an electrical connection portion (terminal connection portion) 11 which is fitted to a mating terminal so as to be electrically connected to the mating terminal, and has, in its back portion, a conductor crimp portion 12 which is crimp-connected to the conductor Wa of the electric wire W through a connection portion 15. The crimp terminal 10 has, in its further back portion, a coating swaged portion 13 which is swaged to a portion of the electric wire W with the coated electric wire Wb.
In the crimp terminal 10, a common terminal bottom plate 10a is extended from the electrical connection portion 11 to the coating swaged portion 13 in a forward/backward direction. The connection portion 15, having a U-shaped cross section, includes a bottom plate 15a common to the terminal bottom plate 10a, and left and right side plates 15b and 15b which stand up from both side edges of the bottom plate 15a in the width direction thereof.
The conductor crimp portion 12 is crimp-connected to the conductor Wa in a state where in the terminal of the electric wire W, an exposed portion of the conductor Wa protruding forward from the insulating coating Wb is placed on the terminal bottom plate 10a. Behind this crimp connection portion 12A, a conductor swaged piece 13 is swaged so as to wrap the coated electric wire Wb of the electric wire W.
The anti-corrosive material 20 is injection-molded with a mold integrally with the electric wire W and the crimp terminal 10 so as to coat the conductor Wa, the circumference of the crimp connection portion 12A of the crimp terminal 10 and the circumference of the insulating coating Wb adjacent to the crimp connection portion 12A.
Specifically, the anti-corrosive material 20 is formed so as to coat the entire portion from a position where the outer circumference of the insulating coating Wb of the electric wire W extended backward of the conductor swaged piece 13 is coated through the front end of the crimp connection portion 12A of the conductor crimp portion 12 to a position at a halfway point of the connection portion 15 in front of the electrical connection portion 11.
When the electric wire with a terminal is manufactured, first, as shown in FIG. 1, the crimp terminal 10 and the electric wire W are crimp-connected (crimp step).
Then, as shown in FIG. 2, the crimp terminal 10 and the electric wire W are set in a mold 100 for injection molding in a state where all the range of the crimp connection portion 12A of the crimp terminal 10 and the electric wire W, the coating swaged portion 13 and the like on which anti-corrosive processing is performed is arranged within the cavity 110 of the mold 100 for molding composed of upper and lower molds 101 and 102 for molding the anti-corrosive material 20 (terminal setting step).
Then, after the terminal setting step, the interior of the cavity 110 of the mold 100 is filled with molten resin 22, and thus the anti-corrosive material 20 is molded (molding step).
After the molding, the mold 100 is released (the upper mold 101 and the lower mold 102 are separated), and thus a molded product is taken out (release step).
Through the steps described above, it is possible to obtain the electric wire with a terminal as shown in FIGS. 3 and 4. The front end portion of the anti-corrosive material 20 is located in the connection portion 15 of the crimp terminal 10, and its cross section is formed as shown in FIG. 5.